Intrathecal complement activation in neurological diseases evaluated by analysis of the terminal complement complex

Area of Science:

• Neurology
• Immunology
• Biochemistry

Background:

• The terminal complement complex (TCC) plays a role in immune responses.
• Its role in neurological diseases requires further investigation, particularly in cerebrospinal fluid (CSF).

Purpose of the Study:

• To determine terminal complement complex (TCC) levels in plasma and CSF of neurological patients.
• To assess the correlation between TCC levels and specific neurological conditions.
• To evaluate TCC as a potential biomarker for intrathecal complement activation.

Main Methods:

• Quantification of TCC in plasma and CSF samples from 208 neurological patients.
• Analysis of TCC levels across different disease categories (infectious, autoimmune, non-inflammatory).
• Correlation analysis with blood-brain barrier function markers (albumin ratio) and CSF total protein.

Main Results:

• Elevated CSF TCC frequencies observed in infectious diseases (80%), radiculoneuritis (62%), multiple sclerosis (30%), and autoimmune diseases (27%).
• Plasma TCC was elevated only in the infectious group.
• No significant correlation found between plasma and CSF TCC, or between CSF TCC and albumin ratio/low CSF protein.

Conclusions:

• Elevated CSF TCC concentration signifies intrathecal complement activation.
• CSF TCC quantification is a valuable tool for diagnosing and examining neurological diseases.
• TCC levels in CSF offer insights into inflammatory processes within the central nervous system.